hen with a respiratory problem?

One of my hens, a 2yr leghorn, seems to have some sort of a cold or respiratory infection. She was sneezing and seems to have trouble breathing, especially after I chased her around the coop to catch her. She has free range with about 15 other chickens and 15 bourbon reds. I brought home 15 chicks about 3 weeks ago but other than that hasn't been exposed to any other poultry and the chicks are not with her although they do share space in a large shed but in separate coops. I confined her away from all the birds and am giving her tetracyline in her water, she seems fairly perky and is eating and drinking well, still getting excited about a handful of scratch grain. So - does anyone have experience with this type of thing? What are the chances she will get better, and even if she does get better will there be a chance she is a carrier for something that could spread to my other birds? Should I cut my losses and butcher her? Are all upper respiratory type symptoms in chickens caused by viruses? We raise our poultry for meat and eggs and I can't stand the thought of this spreading.

I do not recommend antibiotics . Culling sick chickens is my first option with respiratory and intestinal illnesses . I do not eat them either. If there were no other sources possible for this illness then the new chicks are more than likely the carriers . You will have to watch your birds closely. Congenital heart disorders can appear respiratory in nature - with coughing and wheezing - but usually no sneezing.

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